By default, this is set to False. When False, each value from
the repeated fields is stored. When set to True, any trailing
values which are blank will be stripped from the result. If the
underlying field has required=True, but remove_trailing_nulls
is True, then null values are only allowed at the end, and will be
stripped.

This group of fields all share similar functionality for accepting range data.
They are based on MultiValueField. They treat one
omitted value as an unbounded range. They also validate that the lower bound is
not greater than the upper bound. All of these fields use
RangeWidget.